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HelpTest Code LAB3532 Unfractionated Heparin Activity
Clinical System Name
Unfractionated Heparin Activity
Description
Unfractionated heparin (UFH) is used for the prevention and treatment of thromboembolic diseases. The quantitative determination of plasma unfractionated heparin levels is useful for monitoring treatment efficacy.
Sample Requirements
Specimen: Whole Blood
Container(s): Lt Blue/Citrate
Required Vol: (1) 1.8 mL or (1) 2.7 mL
Minimum Vol: N
Note: This is enough for a PT, PTT, TT, Fibrinogen, and UFH to be run on the same sample.
Preferred method of collection is venipuncture with vacuum fill. Test results are affected by incorrect blood volume. Use of a Vascular Access Device for the collection of coag testing is not recommended. Please review the Coagulation Lab Collection Job Aid for detailed instructions.
Processing Instructions: Main Campus
Deliver whole blood to Coag bench. Coag Technologist will process.
Reject due to: clotted, insufficient quantity (underfill), or improper collection (overfill).
Spin: Y
Aliquot: Y
Storage location: Core 14 Freezer ( -70 C).
Specimen should be centrifuged within one hour of collection. Transfer upper 3/4 layer of plasma to plastic tube affixed with large Epic aliquot label. Do not pool. Assay immediately.
Processing Instructions: Offsite & Regional Clinics
Reject due to: clotted, insufficient quantity (underfill), or improper collection (overfill).
Spin: Y
Aliquot: Y
Storage location: -70 C (preferred) or -20 C.
Specimen should be centrifuged within one hour of collection. Double spin, transfer upper 3/4 layer of plasma to plastic tube affixed with large sample label. Freeze one aliquot of plasma at -70 C (preferred) or -20 C. Preferred plasma volume: 1.0 mL, minimum plasma volume: 0.6 mL. Do not pool.
Non-Children's Hospital Offsite collection: Ship completely frozen on dry ice.
Children's Hospital Regional Clinic collection: Ship completely frozen in frozen Nalgene Labtop cooler with ice pack inside an insulated soft cooler.
Stability
| Specimen Type | Temperature | Time |
|---|---|---|
| Citrated platelet-poor plasma | Room temp | ≤4 h |
| Refrigerated | N | |
| Frozen -20 C or -70 C | ≤3 m |
Performing Laboratory
Seattle Children's Laboratory
Department
Department: Coagulation
Phone Number: 206 987-2617 (Client Services)
Synonyms
LAB3532
anti-Xa activity
HEP UNF
Heparin Activity Unfractionated
Heparin Unfractionated
UFH
Availability
| STAT | Performed | TAT |
|---|---|---|
| Y |
Daily |
1 h |
Methodology
Method: Chromogenic substrate assay by STA-R MAX
Analytical Volume: 100 uL plasma
Limitations: Method is affected by moderate lipemia, moderate hemolysis, moderate icterus, insufficient quantity (underfill), improper collection (overfill), improper processing, and improper storage. High hematocrit greater than or equal to 56% requires a citrate adjusted tube.
This assay requires antithrombin III (ATIII) in patient's plasma. Low level of ATIII may underestimate the heparin level.
CPT Codes
85520
Critical Values
≥ 1.10 IU/mL
Therapeutic Range
The therapeutic range for Unfractionated Heparin Activity is 0.3 - 0.6 Anti-Xa IU/mL.
Heparin activity is reported in Anti-Xa IU/mL (Anti-Xa International Units/mL).